Process of mining sulphur



Oct. 12 1926. 1,602,475 B. ANDREWS PROCESS OF MINING SULPHUR Filed Sept. 19, 1924 Qvwewtoz 12 ,Be ija min lndrezus.

351 h flaw tw g;

Patented 0a. 12, 1926,

UNITED STATES BENJAMIN ANDBEWS,,OF HOUSTON, TEXAS.

PROCESS OI MINII ING SULPHUR.

Application filed September, 1924. Serial No. 738,858.

In the mining of sulphur through the employment of the well known Fra'sch system, a tubular well is drilled into the sulphur bearing stratum or formation, and pumps are utilized to force hot water into the sulphur stratum so that the sulphur is melted and flows toward the mouth of an eduction pipe through which it is pumped to the surface in liquid form. Usually air is forced into the sulphur eduction tube so that it mixes with the sulphur near the mouth thereof and so changes the specific gravity of the sulphur column that the sulphur flows readily to the surface where the sulphur is delivered into suitable bins, allowed to cool, and stored, thereafter to be sl1ipped,'according to the demands of the trade. This process has now been in use for many years. However, the eflicient and rofitable mining of sulphur depends lar e y upon whether the lower end of the we 1 pipes are located so that the melted sulphur settles about the mouth of the eduction pipe, or whether it runs off into cavities Wl'llCll exist in the formation at other pointsand which do not drain to the mouth of the eduction pipe. Because of these conditions in the application of the Frasch process, it often happens that wells drilled into the richest part of the sulphur deposit produce only very small quantities of sulphur.

, The object, therefore, of this invention is to provide a method or process whereby the sulphur may be controlled and be given a definite flow toward the mouth of the eduction pipe, so that practically all of the sulphur as melted-Inay be removed without having any considerable portion thereof run off and lost in locations not drained by the eduction pipe. Broadly stated, the improved process comprises forming a cavity beneath the stratum of gypsum containing the sulphur and in the stratum of the underlying rock-salt usually found beneath the sulphur bearing gypsum. This cavity is primarily formed by erosion and by dissolvin comprises the control of the size and lateral extent of this cavity so that the water will be caused to come into contact with the sulphur bearing rock at desired oints.

For a detailed description 0 one form of the improved rocess which is at present deemed prefera- 1e, reference may be had to the followin specification and to the accompanying drawing in which the figure ilthe rock-salt. My invention also.

lustrated shows one arran ement of well pipes in section and arrange in such a manner that the principle of my improved process may be indicated.

In the drawing, the numeral 1 indicates the usual outer well casin or pipe. Through this passes the conve mg ipe for the hot water or similar liqui emp oyedto melt the sulphur, which liquid is supplied through the branch pipe 3. Within the pipe 2 is the sulphur carrying eduction pipe 4. This is provided with an outlet pipe 6 which leads to suitable bin or other containers in which the sulphur is cooled and stored. The

. branch pipe 5 is also provided, which may be used to introduce hot water or otherv liquid when desired. The inner pipe 7 passes through the sulphur pipe 4 and is for the purpose of supplying air under pres sure to the lower end of said sulphur pipe to change the specific gravity of the sulphur column so that the sulphur may be easily raised to the top of the well and withdrawn through the pipe 6 otherwise. The parts thus referred to are those well known in the commonly used methods of mining of sulphur, but may be varied or arranged in other ways to suit various conditions and circumstances.

-In practicing the improved process, the well pipes are introduced by drilling or otherwise through the surface soil and various strata of clays and shale, etc, as indicated b the numeral 8. However, instead of drilling to the central portion of the sulphur deposit or stratum 9, the well is drilled completely through the sulphur stratum and into the underlying stratum of rock-salt 10. It has been found that the underlying material in practically all of the sulphurbearing formations along the Gulf Coast of the United States where sulphur is now obtained in large quantities, comprises a deposit of pure rock-salt. This deposit of salt is homogeneous and without crevices or passages, and often attains a thickness of several thousand feet.

One object of this invention is to utilize this deposit of rock-salt so that a cavity may be formed beneath the sulphur bearing stratum or deposit. As' above referredto, this is accomplished primarily by drilling throu h the sulphur bearing stratum and for a slig t distance further, which may be 5 to '15 feet, more or less, accordin to circumstances. When the drilling as been gypsum or rock. The temperature of this water is lower than the melting point of sulphurbut of such temperature that the rocksalt is readily dissolved thereby. As soon as a suitable cavity has been formed, hot wateris introduced through the pipes 3 and 2 in order to melt the sulphurso that the sulphur above the cavity 11 is melted and caused to flow under the action of ravity to the bottom thereof, as indicated hy the numeral 12. The sulphur thereafter melted is then removed by action of the air and the pum s in the usual manner. It should be noted, ow ever, that when the sulphur flows downward to the bottom of the cavity 11 it will form a thin layer upon the surface of the rock-salt or other material at the bottom thereof, the thickness of which depends upon the position of the end of the eduction pipe and the rate of withdrawal of the melted sulphur. This forms a protective coating and prevents the action of the hot water from dissolving further salt beneath the melted sulphur. The' dissolving and eroding action of the hot water may continue, however, in lateral directions beneath the sulphur bearing stratum, as indicated by the dotted lines 13 in the figure of the drawing. In this manner, the active area of the hot water, contacting with the sul hur deposit, is graduall'y e'xtended, there y causing more rock-salt to be dissolved and allowing additional portions of the sulphur deposit to be acted upon by the hot water. This extension of the cavity may continue to cover a large area, which may be several acres in extent.

Thus the lateral enlargement of cavity in the rock-salt is automatically controlled and the solvent action of the hot'water is con fined to lateral extensionsof the cavity in rock-salt and takesplace only when the sulphur is pum ed out to a level below that of the bottom 0 the overlying gypsum. For this reason the cavity in the rock-salt is not enlarged until the sulphur is pumped out faster than it enters the cavity and it thus is enlarged laterally only, the sul hur itself being melted out of'the gypsum a ove the level of the surface of the melted sulphur.

It will be seen that I have provided a process b which practically all the sulphur in a sulp ur-bearing stratum or deposit may be removed without any considerable loss by the stopping of! action of the melted sulphur below the end of the eduction pipe, as carried out in the commonly used processes. If it be desired to prevent a flow of hot aeeaera water upwardly into the'pores or passages in the sulphur bearing deposit, thereby causing the water to flow laterally, it may introduce into the hot water a slight comminuted material, such as saw-dust, so that the pores or passages in the sulphur deposit or gypsum will be filled therewith and prevent the flow of the heat-carrying liquid in an upward direction. Thus the action of the hotwater will be controlled to a greater or less extent, so that its action will be extended laterally to a greater extent than otherwise might be the case it the pores and passages in the sulphur bearing stratum be allowed to be filled with and carry off the hot water.

-Having described this form of my invention, ll do not wish to be understood as being limited to the details of procedure there in set forth, for various changes may be made by those skilled in the art without departing from the spirit and scope of my invention,

prises drilling completely through a sulphur bearing stratum and into the underlying rock-salt, supplying a flow of a solvent for the salt at a temperature below' the melting point of sulphur to form a cavity in said stratum of rock-salt, and then supplying a heated fluid to melt and permit transfer of the sulphur to the surface'and at the same time causing the sulphur to cover the bottom of the cavity and allow extension thereot' laterally only.

2. The process of mining sulphur when overlyin rock-salt which comprises drilling complete y through a sulphur bearing stratum and into an underlying stratum of rocksalt, supplying a flow of water at a temperature below the melting point of sulphur and under pressure to form a cavity in said stratum o'f.rock salt, and then supplying heated water to melt andpermit transfer of the sulphuric; the surface.

3. The' process of mining sulphur when overlying rock-salt which comprises drilling completely through a sulphur bearing stratum and into an underlying stratum of rocksa-lt, supplying at a temperature below the melting point of sulphur a flow of a liquid in which rock-salt is soluble to form a cavity therein, supplying a heated fluid to melt and permit transfer of the sulphur to the surface, and then introducing into said liquid a light comminuted material which will float thereon and close pores or passages at desired points on the lower side of said sulphur stratum when the sulphur has been removed therefrom to the desired height.

Signed at New York, N. Y., September BENJAMIN ANDREWS. 

